Trangia do a 500ml option that might work. They also do a 300ml option - dimensions are available on the trangia site. Straps are easily found or (random idea) you could chain together a couple of toe straps if you have any of the nylon ones.
Ive found that the old fashioned sig bottle fits with a bit of tinkering. Its not the best fuel bottle, but they were used for years before modern safety fuel bottles came along.
I love my trangia so much.
On the hunt for a smaller fuel bottle that fits my bottle cage nicely, and a replacement strap. Lost it on South Downs last summer. And the strap.